PNAS：生命早期的端粒长度可预测寿命

一项研究发现，个体的端粒——这是在染色体的两端形成了保护帽的重复的DNA序列——的长度可能预测寿命。

Pat Monaghan及其同事测量了斑马雀从雏鸟阶段到自然寿命末期的端粒长度。这种鸟的自然寿命从210天到将近9年不等。端粒的缩短与正常衰老以及各种退行性疾病都有联系，但是此前的研究没有把端粒长度和总寿命联系起来。

这组科研人员发现，在生命非常早的阶段测量的端粒长度对斑马雀的寿命有最高的预测能力：有最长的端粒的25日龄的小鸟也有最长的寿命。端粒长度随着年龄而减少，最显著的长度减少发生在生命的第一年中。然而，长度减少率并不能预测生存，而且长寿的个体比短命的个体在年龄的各个阶段都有更长的端粒。

这组作者说，这些发现表明了25日龄的端粒长度能够强有力地预测最终的寿命，但是仍然不清楚为什么某些个体比另一些个体的端粒更长。

Telomere length in early life predicts lifespan

Britt J. Heidingera,Jonathan D. Blounta, Winnie Bonera,Kate Griffithsa,Pat Monaghana

The attrition of telomeres, the ends of eukaryote chromosomes, is thought to play an important role in cell deterioration with advancing age. The observed variation in telomere length among individuals of the same age is therefore thought to be related to variation in potential longevity. Studies of this relationship are hampered by the time scale over which individuals need to be followed, particularly in long-lived species where lifespan variation is greatest. So far, data are based either on simple comparisons of telomere length among different age classes or on individuals whose telomere length is measured at most twice and whose subsequent survival is monitored for only a short proportion of the typical lifespan. Both approaches are subject to bias. Key studies, in which telomere length is tracked from early in life, and actual lifespan recorded, have been lacking. We measured telomere length in zebra finches (n = 99) from the nestling stage and at various points thereafter, and recorded their natural lifespan (which varied from less than 1 to almost 9 y). We found telomere length at 25 d to be a very strong predictor of realized lifespan (P < 0.001); those individuals living longest had relatively long telomeres at all points at which they were measured. Reproduction increased adult telomere loss, but this effect appeared transient and did not influence survival. Our results provide the strongest evidence available of the relationship between telomere length and lifespan and emphasize the importance of understanding factors that determine early life telomere length.

文献链接：http://www.pnas.org/content/early/2012/01/04/1113306109.abstract